Telephone terminal blocks usually have a large number of connectors mounted on a distributor base plate. These connectors conncet incoming telephone lines (main wires) with outgoing lines (switching wires). U.S. Pat. No. 4,431,247 discloses an electrical connector for this purpose having a hollow cylindrical contact element with a circumferential wire connection slot and a cap rotatable about the contact element and having a transverse wire channel for receiving an outgoing wire end and for carrying it into the wire connection slot upon rotation of the cap. The end of the cylindrical contact element opposite the cap is attached to an electrically insulating support stud which forms a part of the distributor base plate. A contact-lug extends from the end of the contact element through an opening in the support stud to the bottom side of the distributor base plate, where it may be connected to one of the incoming lines. Above the distributor base plate, an outgoing line can be readily connected or disconnected by rotation of the cap. Each time an alteration of the circuitry powered by the outgoing line wires is needed, the connections of the outgoing lines have to be changed, while the incoming line connections may remain unchanged. Therefore, the lower part of the distributor base plate is in most practical situations prepared as a box-like structure permanently filled with a sealing compound to securely protect the connections of the incoming lines. The casting of this sealing compound is usually done in the factory, in which case the connecting elements for the incoming lines are formed as short conductor stubs with a coupling adapter at their ends. The arriving incoming line wires will, then, be connected to a matching counter-adapter and the two adapter pieces will be connected with each other. However, if incoming line wires have to be exchanged, a changing of wires is necessary at both adapter pieces and such an exchange at the location of use is difficult.
In many telecommunication systems it is necessary to switch incoming line wires (main wires in a distributor or to connect the incoming line wires directly to the distributor without the intermediate connections of adapter pieces. In these cases, the connector of U.S. Pat. No. 4,431,247 is not suitable.
The electrical connector of the present invention has a hollow cylindrical electrically conductive contact element, a cap and a tubular sleeve of an electrically insulating material and a locking mechanism. The contact element has a pair of parallel wire connection slots extending in a circumferential direction, each wire connection slot extending from a relatively wide insertion area to a narrow insulation cutting and wire core connection clamping area. The cap is positioned over said contact element and has a first transverse channel in axial alignment with a first of the wire connection slots in the contact element for receiving the end of an insulated electrical wire. The cap is rotatable about the contact element between an insertion position and a wire connection position whereby the first transverse channel is aligned with either the wire insertion area or the clamping area of the first wire connection slot. The tubular sleeve is fitted on said contact element and has a second transverse channel in axial alignment with the second of the wire connection slots in the contact element for receiving the end of an insulated electrical wire. The tubular sleeve is rotatable about the contact element between an insertion position and a wire connection position whereby the second transverse channel is aligned with either the wire insertion area or the clamping area of said second wire connection slot. The locking mechanism is provided for locking the tubular sleeve in its wire connection position. The electrical connector of the present invention permits a simple, exchangeable connection of the incoming line wires as well as the outgoing line wires without significant additional space requirements.